Understanding the structure–property relationships of the ferroelectric to relaxor transition of the (1 − x)BaTiO3–(x)BiInO3 lead-free piezoelectric system

• Published in: Journal of materials science 2017-05, Vol.52 (9), p.5309-5323
• Main Authors: Manjón-Sanz, Alicia, Berger, Caitlin, Dolgos, Michelle R.
• Format: Article
• Language: English
• Subjects: Actuators; Barium titanates; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Dielectric relaxation; Electric fields; Ferroelectric materials; Ferroelectricity; Lead free; Materials Science; Original Paper; Phase transitions; Piezoelectricity; Polarization; Polymer Sciences; Relaxors; Solid Mechanics; Temperature dependence
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-017-0770-x

A structural and electromechanical investigation has been performed on (1 −  x )BaTiO 3 –( x )BiInO 3 in the region 0.03 ≤  x  ≤ 0.12. A gradual structural phase transition has been observed where the structure changes from tetragonal ( P 4 mm ) and passes through two regions of coexisting phases: (1) P 4 mm  +  R 3 m in the range 0.03 ≤  x  ≤ 0.075 and (2) P m 3 ¯ m  +  R 3 m for 0.10 ≤  x  ≤ 0.12. The properties also transition from ferroelectric ( x  ≤ 0.03) to relaxor ferroelectric ( x  ≥ 0.05) as the dielectric permittivity maximum becomes temperature and frequency dependent. This transition was also confirmed via polarization-electric field measurements as well as strain-electric field measurements. At the critical composition of x  = 0.065, a moderate strain of ~0.104% and an effective piezoelectric coefficient ( d 33 * ) of 260 pm/V were observed. The original purpose of this study was to demonstrate the polarization extension mechanism as predicted in the literature, but due to the ferroelectric to relaxor transition, this mechanism was not found to be present in this system. However, this demonstrates that BaTiO 3 -based lead-free ceramics could be modified to obtain enhanced electromechanical properties for actuator applications.